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United States Patent |
6,008,450
|
Ohtsuka
,   et al.
|
December 28, 1999
|
Solar cell module having a back face reinforcing member covered by a
resin and a process for the production of said solar cell module
Abstract
A highly reliable molar cell module comprising a back face reinforcing
metallic member, a photovoltaic element, a filler for encapsulating said
photovoltaic element, and a surface protective film having a
weatherability, wherein the end faces of said back face reinforcing
metallic member and a partial area of the rear face of said back face
reinforcing metallic member are covered by a resin. A process for the
production of said solar module by way of thermocompression bonding
process.
Inventors:
|
Ohtsuka; Takashi (Tsuzuki-gun, JP);
Fukae; Kimitoshi (Nara, JP);
Inoue; Yuji (Nara, JP)
|
Assignee:
|
Canon Kabushiki Kaisha (Tokyo, JP)
|
Appl. No.:
|
749634 |
Filed:
|
November 15, 1996 |
Foreign Application Priority Data
Current U.S. Class: |
136/251; 52/173.3; 136/259; 438/66 |
Intern'l Class: |
H01L 025/00 |
Field of Search: |
136/251,259
52/173.3
438/66
|
References Cited
U.S. Patent Documents
5252141 | Oct., 1993 | Inoue et al. | 136/251.
|
5589006 | Dec., 1996 | Itoyama et al. | 136/248.
|
5733382 | Mar., 1998 | Hanoka | 136/251.
|
Primary Examiner: Chapman; Mark
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper & Scinto
Claims
What is claimed is:
1. A solar cell module comprising a photovoltaic element, a filler for
encapsulating said photovoltaic element, and a back face reinforcing
metallic member,
wherein said filler encapsulating said photovoltaic element is situated on
a front face of said back face reinforcing metallic member, and
wherein end faces of said back face reinforcing metallic member and a
partial area of a rear face of said back face reinforcing metallic member
are covered by a resin.
2. A solar cell module according to claim 1, wherein the back face
reinforcing metallic member is applied with plasticity processing.
3. A solar cell module according to claim 1, wherein the back face
reinforcing metallic member comprises a steel plate.
4. A solar cell module according to claim 1, wherein the filler comprises a
thermoplastic resin.
5. A solar cell module according to claim 1, wherein the resin by which the
end faces of the back face reinforcing metallic member and the partial
area of the rear face of the back face reinforcing metallic member are
covered is a thermoplastic resin.
6. A solar cell module according to claim 5, wherein the thermoplastic
resin is the same as the filler.
7. A solar cell module according to claim 1, wherein the photovoltaic
element has flexibility.
8. A solar cell module according to claim 1, wherein the photovoltaic
element comprises an amorphous silicon material.
9. A solar cell module according to claim 1 which further comprises a
surface protective film having a weatherability.
10. A solar cell module according to claim 1, wherein the filler and the
resin by which the end faces of the back face reinforcing metallic member
and the partial area of the rear face of the back face reinforcing
metallic member are covered are the same.
11. A solar cell module according to claim 1, wherein the resin situated on
the rear face of the back face reinforcing metallic member is continued
from the resin covering the end faces of the back face reinforcing
metallic member.
12. A solar cell module according to claim 1, wherein the resin by which
the end faces of the back face reinforcing metallic member and the partial
area of the rear face of the back face reinforcing metallic member are
covered comprises a resin selected from the group consisting of
ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, polyvinyl
butyral, silicone resin and acrylic resin.
13. A solar cell module according to claim 1, wherein the filler comprises
a resin selected from the group consisting of ethylene-vinyl acetate
copolymer, ethylene-acrylate copolymer, polyvinyl butyral, silicone resin
and acrylic resin.
14. A solar cell module according to claim 1, wherein the back face
reinforcing metallic member is applied with coating treatment.
15. A solar cell module according to claim 1 which further comprises a
filler-retaining member.
16. A solar cell module according to claim 15, wherein the filler-retaining
member comprises a woven member or a nonwoven member.
17. A process for producing a solar cell module, said process comprising:
(a) a preparation step of stacking a filler material, a photovoltaic
element and a back face reinforcing metallic member in the named order to
form a stacked body on a mounting table, and arranging a resin material
over said stacked body so as to cover peripheries containing end portions
of said back face reinforcing metallic member, and
(b) a sealing and uniting step of subjecting said stacked body to heat
treatment.
18. The process according to claim 17, wherein the sealing and uniting step
(b) includes a further step which is conducted prior to subjecting the
stacked body to heat treatment, said further step comprising covering the
stacked body formed in the preparation step (a) by a covering sheet to
hermetically enclose the stacked body between said covering sheet and the
mounting table and exhausting the space containing the stacked body
between the covering sheet and the mounting table.
19. The process according to claim 17 which further comprises a step of
subjecting the stacked body having been subjected to heat treatment in the
sealing and uniting step (b) to bending treatment to bend opposite
photovoltaic element-free end portions of the stacked body.
20. A process for producing a solar cell module, said process comprising
the steps of:
(a) forming a stacked body comprising a filler material, a photovoltaic
element and a back face reinforcing metallic member on a mounting table
having a protruded portion such that said stacked body is situated on said
protruded portion,
(b) covering said stacked body by a covering sheet so as to hermetically
enclose said stacked body between said covering sheet and said mounting
table, and
(c) heating and uniting said stacked body while exhausting the space
containing said stacked body between said covering sheet and said mounting
table.
21. A process for producing a solar cell module, said process comprising
the steps of:
(a) forming a stacked body comprising a filler material, a photovoltaic
element and a back face reinforcing metallic member on a mounting table
having a protruded portion circumscribed by a groove such that said
stacked body is situated on said protruded portion,
(b) covering said stacked body by a covering sheet so as to hermetically
enclose said stacked body between said covering sheet and said mounting
table, and
(c) heating and uniting said stacked body while exhausting the space
containing said stacked body between said covering sheet and said mounting
table.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a highly reliable solar cell module having
an improved back face reinforcing member. More particularly, the present
invention relates to a highly reliable solar cell module having a back
face reinforcing member covered by a resin which is hardly deteriorated,
which is free of layer separation at the interface between the back face
reinforcing member and the filler. The present invention further relates
to a process for producing said solar cell module.
2. Related Background Art
In recent years, public attention has been focused on solar cells capable
of serving as a clean and non-exhaustable power generation source of
supplying electric power without causing air pollution.
In order to use such a solar cell as a power generation source, it is
usually designed into a solar cell module in a desired configuration which
can be used as the power generation source. And such a solar cell module
has been widely using in practice as the power generation source by
installing it, for instance, on the ground or on a roof of a building. And
it is expected to be usable as a large scale power generation source in
the future.
In the case of a solar cell module configured such that it can be used by
integrating with a building roof member (this solar cell module will be
hereinafter referred to as building roof-unifying type solar cell module),
it has advantages such that it is not necessary to use a particular
supporting table therefor, and its installation can be conducted as a part
of the building construction works and it is therefore possible to
markedly reduce the installation costs.
In any case, for a solar cell, it is required to have sufficient durability
against external environments such as temperature, humidity, external
shocks and the like. Therefore, a conventional solar cell module is
structured such that a solar cell (or a photovoltaic element) is sealed by
a filler and a weatherable film or a glass plate as a protective member is
disposed on the light incident side.
A particularly advantageous structure for a building roof-unifying type
solar cell module is that a weatherable film as a surface protective
member is disposed on the light incident side, a back face reinforcing
member is disposed on the rear face side without using a frame at the
periphery, and the non-power generation region containing the back face
reinforcing member is bent by way of plasticity processing.
In the case of such a solar cell module having an improved physical
strength attained by way of the bending treatment without using a frame,
there are such advantages as will be described in the following. Because
the solar cell module is free of a frame-related junction, no waterproof
treatment is required to be conducted, and when it is used as a roof
member of a building, it desirably functions to shelter from the rain. In
addition, since no frame is used, it can be produced with a reasonable
production cost. Further, the weight of the solar cell module is lighter
than that of a solar cell module provided with a frame, and it can be
readily handled. Besides these advantages, there is also an advantage in
that when upon the installation, while taking advantage of the rigidity of
the solar cell module, it can be readily connected with or laminated to
other member by virtue of its flexibility, and therefore, it can be
installed in a persistent and reliable state.
In the case where as the back face reinforcing member, a metallic member
which is usually used as a metallic roof member of a building is used, the
solar cell module can be processed and installed in a similar manner in
the case of a ordinary roof member. This situation attains not only the
formation of a reliable roof but also an improvement in the compatibility
of the solar cell module with a metallic roof member.
However, for such a solar cell module provided with a back face reinforcing
metallic member and having a plasticity-processed non-power generation
region containing the back face reinforcing metallic member, when it is
installed on a metallic roof of a building, there is a drawback due to
corrosion of the metallic roof. Particularly, in the case of an ordinary
metallic roof of a building, when it is corroded, the coating film thereof
is raised and swelled to entail layer separation and other problems such
as the occurrence of rusts including white and red rusts, and the like,
where not only the exterior appearance of the roof is marred but also the
roof is often bored into a useless state. These problems are significant
when the metallic roof is exposed to salt-containing wind near the
seashore or to acid rain containing corrosive materials caused due to
changes in the environments such as air pollution.
In the case where a conventional solar cell module having a solar cell (a
photovoltaic element) positioned on the surface side while being sealed by
a covering material comprising a filler and a weatherable film is
installed on the metallic roof, due to the foregoing rusts caused at the
metallic roof, the solar cell module sometimes suffers from such problems
as will be described in the following. The rusts sometimes invade into the
inside of the solar cell module through its end portion to color or swell
the covering material, where layer separation is liable to occur at the
end portion of the solar cell module. These problems result in not only
hindering the exterior appearance of the solar cell module but also
deteriorating the performance of the solar cell.
Further, there is a tendency for the conventional solar cell module to have
such problem as will be described in the following. That is, as above
described, the solar cell is positioned on the surface side in the
conventional solar cell module and because of this, it is extremely
difficult to conduct maintenance works such as repacking even at the
initial stage when a rust first occurs. Further, the solar cell module is
usually installed on the roof on condition that it is used over a long
period of time and therefore, it is not desirable to conduct reroofing as
in the case of an ordinary metallic roof. In view of these situations, it
is important for the solar cell module to be protected from being rusted.
And there is a demand for improving the solar cell module so that no rust
is occurred at the edge portions of the back face reinforcing metallic
member.
Further in addition, for the conventional solar cell module, its edge
portions are externally exposed and because of this, a problem is liable
to entail in that because the edge portions of the back face reinforcing
metallic member are externally exposed, when the solar cell module is
continuously used in outdoors over a long period of time, the adhesion
between the filler and the back face reinforcing metallic member is
deteriorated to cause layer separation at the interface between the filler
and the back face reinforcing metallic member. This problem is liable to
readily occur at portions of the back face reinforcing metallic member
which have been applied with plasticity-processing treatment such as bend
treatment. Particularly, when the back face reinforcing metallic member is
bent toward the direction where no filler is bonded, said problem is more
liable to occur due to a bending distortion subjected to the filler.
Besides these problems, there is a tendency for the conventional solar cell
module to have a further problem such that in the transportation, bending
treatment or installation works therefor, when the solar cell module is
contacted with other solar cell module, they are damaged with each other
because of the exposed edge portions of their back face reinforcing
metallic members. Particularly, in the case where the solar cell module is
installed on a roof of a building, there is an occasion that an worker
having little knowledge about how to handle the solar cell module is
engaged in the installation work and he erroneously make the solar cell
module contact with other solar cell module. In this case, the back face
reinforcing metallic member of one of the solar cell modules has exposed
sharp edge portions (or cut faces), the weatherable film as the surface
protective film of the other solar cell module is damaged by said exposed
sharp edge portions, where the damaged solar cell module becomes useless.
Further, in the case of subjecting a conventional solar cell module to
bending treatment using a roller forming equipment having a pair of soft
pressure rollers made of urethane resin or the like, a problem is liable
to entail in that the exposed edge portion of the back face reinforcing
metallic member damage the pressure rollers to shorten their lifetime.
SUMMARY OF THE INVENTION
An object of the present invention is to eliminate the foregoing problems
in the prior art and provide a highly reliable solar cell module which is
free from the problems found in the prior art.
Another object of the present invention is to provide a highly reliable
solar cell module which can be desirably used by installing on a metallic
roof of a building where it exhibits a desirable photoelectric conversion
performance even when continuously used over a long period of time,
without the occurrence of the foregoing problems due to the corrosion of
the metallic roof found in the prior art.
A further object of the present invention is to provide a highly reliable
solar cell module with no necessity of using a protecting means such as a
metallic cover for preventing the occurrence of layer separation at the
interface between the filler and the back face reinforcing metallic member
and which can be desirably used as a roof member of a building.
A further object of the present invention is to provide a highly reliable
solar cell module comprising a photovoltaic element (or a solar cell), a
filler for encapsulating said photovoltaic element, and a back face
reinforcing metallic member, wherein the end faces of said back face
reinforcing metallic member and a partial area of the rear face of said
back face reinforcing metallic member are covered by a resin.
A further object of the present invention is to provide a process for
producing a solar cell module, comprising (a) a preparation step of
stacking a filler material, a photovoltaic element (or a solar cell) and a
back face reinforcing metallic member in the named order on a mounting
table, and arranging a resin material so as to cover an end surface of
said back face reinforcing metallic member and an end surface of said
filler material while covering end faces of said back face reinforcing
metallic member to form a stacked body situated on said mounting table,
and (b) a sealing and uniting step of subjecting said stacked body to heat
treatment.
A further object of the present invention is to provide a process for
producing a solar cell module, comprising the steps of (a) providing a
mounting table having a protruded table, (b) forming a stacked body
comprising a filler material, a photovoltaic element (or a solar cell) and
a back face reinforcing metallic member on said protruded table of the
mounting table, (c) covering said stacked body by a covering sheet so as
to hermetically enclose said stacked body between said covering sheet and
said mounting table, and (d) heating and uniting said stacked body while
exhausting the space containing said stacked body between said covering
sheet and said mounting table.
A further object of the present invention is to provide a process for
producing a solar cell module, comprising the steps of (a) providing a
mounting table having a protruded table circumscribed by a recession, (b)
forming a stacked body comprising a filler material, a photovoltaic
element (or a solar cell) and a back face reinforcing metallic member on
said protruded table of the mounting table, (c) covering said stacked body
by a covering sheet so as to hermetically enclose said stacked body
between said covering sheet and said mounting table, and (d) heating and
uniting said stacked body while exhausting the space containing said
stacked body between said covering sheet and said mounting table.
In the present invention, by covering the end faces of the back face
reinforcing metallic member of the solar cell module by a rein, the back
face reinforcing metallic member is effectively prevented from being
deteriorated or corroded. This situation provides advantages in that the
coated film of the back face reinforcing metallic member, which is
situated in the vicinity of the end portions of the back face reinforcing
metallic member, is prevented from being colored, separated and raised.
And by covering a partial area of the rear face of the back face
reinforcing metallic member by an extended portion of said resin, layer
separation at the interface between the back face reinforcing metallic
member and the filler is effectively prevented.
The above situations provides further advantages as will be described in
the following. Not only during bending treatment of the solar cell module
but also during transportation and installation of the solar cell module,
there is not such an occasion that the solar cell modules are not damaged
by the end portions of their back face reinforcing metallic members when
they are contacted with each other and therefore, the occurrence of a
defective solar cell module is prevented. In the case where the solar cell
module is subjected to bending treatment by means of the roller forming
equipment, the pressure rollers are prevented from being worn. Further, it
is not necessary to use a metallic cover in order to prevent the back face
reinforcing metallic member from being separated from the filler, and this
situation makes it possible to establish a desirable roof of a simple
configuration and having a good exterior appearance when the solar cell
module is used as a roof member of a building. In this case, since such
metallic cover as above described is not used, there is free of a problem
found in the case of using the metallic cover in that dusts or the like
are accumulated on the metallic cover. And there can be attained a
reduction in the costs required in the roofing by solar cell modules.
Further in addition, the protected solar cell-free end portions of the
solar cell module according to the present invention can be bent into a
complicate configuration as desired, which is satisfactory in terms of
protection.
The solar cell module according to the present invention can be desirably
installed at a desired location as a power generation source. For
instance, it can be installed on a roof of a building where it can serve
also as a constituent member of the roof as above described. It can be
also installed on an appropriate support table or on the ground. Further,
it can be installed, for example, on a sound-proof wall where it can be
serve also as a constituent member of the sound-proof wall.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic slant view illustrating the configuration of an
example of a solar cell module according to the present invention.
FIG. 2 is a schematic cross-sectional view, taken along the line A-A' in
FIG. 1.
FIG. 3 is a schematic cross-sectional view illustrating the constitution of
an example of a photovoltaic element (or a solar cell) which can be used
in the present invention.
FIGS. 4 and 5 are schematic views for explaining a example of a process for
producing a solar cell module according to the present invention.
FIGS. 6, 7 and 8 are schematic views for explaining another example of a
process for producing a solar cell module according to the present
invention.
FIG. 9 is a schematic cross-sectional view illustrating the configuration
of an example of a principal end portion of a solar cell module according
to the present invention.
FIG. 10 is a schematic slant view illustrating the configuration of a
further example of a solar cell module according to the present invention.
FIG. 11 is a schematic cross-sectional view illustrating the configuration
of an example of a conventional solar cell module.
FIG. 12 is a schematic slant view illustrating the configuration of another
example of a conventional solar cell module.
FIG. 13 is a schematic cross-sectional view, taken along the line B-B' in
FIG. 12.
DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS
The present invention attains the above-described objects.
The present invention will be described with reference to the following
embodiments. It should be understood that the scope of the present
invention is not restricted to these embodiments.
As above described, the present invention provides a highly reliable solar
cell module comprising a photovoltaic element (or a solar cell), a filler
for encapsulating said photovoltaic element, and a back face reinforcing
metallic element, wherein the end faces of said back face reinforcing
metallic member and a partial area of the rear face of said back face
reinforcing metallic member are covered by a resin.
The resin situated on the rear face of the back face reinforcing metallic
member may be continued from the resin of covering the end faces of the
back face reinforcing metallic member.
The resin by which the end faces of said back face reinforcing metallic
member are covered and that by which the partial area of the rear face of
said back face reinforcing metallic member may be the same as the resin by
which the filler is constituted.
The solar cell module according to the present invention may have a surface
protective film comprising a weatherable film on the light incident side.
FIG. 1 is a schematic slant view illustrating the configuration of a
typical example of a solar cell module according to the present invention.
FIG. 2 is a schematic cross-sectional view, taken along the line A-A' in
FIG. 1.
In FIGS. 1 and 2, reference numeral 101 indicates a photovoltaic element
(or a solar cell) enclosed in the solar cell module (see, FIG. 1),
reference numeral 102 indicates a back face reinforcing metallic member,
reference numeral 103 a weatherable film as a surface protective film,
reference numeral 104 a filler (comprising a resin) for encapsulating said
photovoltaic element 101, and reference numeral 105 a resin of covering
the end faces of said back face reinforcing metallic member 102 while
covering a partial area of the rear face of the back face reinforcing
metallic member.
In FIG. 2, the photovoltaic element 101 is embedded in the filler 104. But
this is omitted in FIG. 2.
The solar cell module shown in FIGS. 1 and 2 has opposite bent non-power
generation regions which enable to readily install the solar cell module
at a desired location, for instance, on a roof of a building.
In the following, description will be made of each constituent of the solar
cell module according to the present invention.
Photovoltaic Element 101 (or Solar Cell)
For the photovoltaic element 101 (or the solar cell) used in the present
invention, there is no particular limitation. Any photovoltaic elements
(or any solar cells) may be optionally used as long as they exhibit a
photoelectric conversion performance as desired. However, it is desired to
use a photovoltaic element (or a solar cell) which is thin and has a high
shock resistance and a bending property. Specifically the photovoltaic
element (or the solar cell) desirably usable in the present invention can
include those having a substrate constituted by a metal or resin.
Particularly, it is preferably to use an amorphous solar cell formed on a
stainless steel substrate.
FIG. 3 is a schematic cross-sectional view illustrating a typical example
of a photovoltaic element (or a solar cell) usable in the present
invention.
In FIG. 3, reference numeral 301 indicates an electrically conductive
substrate, reference numeral 302 a back reflecting layer, reference
numeral 303 a semiconductor photoactive layer, reference numeral 304 a
transparent and electrically conductive layer, and reference numeral 305 a
collecting electrode (or a grid electrode).
The photovoltaic element shown in FIG. 3 comprises the back reflecting
layer 302, the semiconductor photoactive layer 303, the transparent and
electrically conductive layer 304, and the collecting electrode 305
disposed in the named order on the electrically conductive substrate 301,
where an power outputting terminal (not shown) is electrically connected
to the collecting electrode 305 and it is extending from the collecting
electrode 305 while being insulated, and another outputting terminal (not
shown) is electrically connected to the electrically conductive substrate
301.
The semiconductor photoactive layer 303 functions to conduct photoelectric
conversions The semiconductor photoactive layer may be composed of a
single crystal silicon semiconductor material, a non-single crystal
silicon semiconductor material such as an amorphous silicon semiconductor
material (including a microcrystalline silicon semiconductor material) or
polycrystalline silicon semiconductor material, or a compound
semiconductor material. In any case, the semiconductor photoactive layer
comprised of any of these semiconductor materials may be of a stacked
structure with a pin junction, a pn junction or a shottky type junction.
As the ptotovoltaic element 101 (or the solar cell) in the solar cell
module shown in FIGS. 1 and 2 may be a solar cell comprising a plurality
of photovoltaic elements having the above-described constitution
integrated in series connection or in parallel connection depending upon a
desired voltage or electric current.
Back Face Reinforcing Metallic Member 102
The back face reinforcing metallic member 102 serves to make the solar cell
module have a sufficient physical strength in terms of structure and to
prevent the solar cell module from being distorted or warped due to
changes in the environmental atmosphere.
The back face reinforcing metallic member is desired to comprise a metallic
member having a desired thickness which enables to make the solar cell
module have a sufficient physical strength in terms of structure when its
opposite end portions each belonging to the non-power generation region of
the solar cell module are bent by way of forming treatment. Hence, the
metallic member is desired to have a bendability and an excellent
processing suitability. For the thickness of the metallic member as the
back face reinforcing metallic member, it is desired to be in the range of
from 0.2 mm to 2.0 mm.
The metallic member as the back face reinforcing metallic member is desired
to excel in weatherability and corrosion resistance. In the case where the
metallic member is not sufficient in terms of weatherability and corrosion
resistance, it can be made to have a sufficient weatherability and
corrosion resistance by subjecting to rust preventive treatment.
Further, the metallic member as the back face reinforcing metallic member
is desired to have a sufficient adhesion with a layer such as a filler
layer as the filler 104 and an adhesive which will be occasionally used.
Specific examples of the metallic member usable as the back face
reinforcing metallic member are steel plates such as copper plate,
aluminum alloy plate, lead plate, zinc plate, titanium plate, and
stainless steel plate; special plated-steel plates such as Zn-plated steel
plate, and Zn-Al alloy-plated steel plate; layered steel plates; and
coated steel plates.
The back face reinforcing member has an effect on the exterior appearance
of the solar cell depending on the installation configuration employed for
the solar cell module. Therefore, it is desired to selectively use an
appropriate metallic member having a desired color hue as the back face
reinforcing metallic member depending on the installation configuration
employed for the solar cell module. In this case, it is possible to color
the metallic member as the back face reinforcing metallic member by
coating it with a polyester resin series paint or an epoxy resin series
paint in a state of having a desired color hue. Alternatively, the
metallic member may be laminated with a desirably colored film in a state
of having a desired color hue.
Resin 105
As above described, the end portions of the back face reinforcing metallic
member 102 are covered by the resin 105 while the resin 105 covering also
a partial area of the rear face of the back face reinforcing metallic
member.
Particularly, it is necessary for the resin 105 to cover the end portions
of the back face reinforcing metallic member 102 such that the resin
covers at least the end cut faces of the back face reinforcing metallic
member while the resin being extending to the rear face of the back face
reinforcing metallic member, namely the back face reinforcing metallic
member's face which intersects with said end cut faces on the side on the
side where no photovoltaic element is arranged, to cover a partial area of
said rear face.
For the shape of the resin 105 of covering the end portions of the back
face reinforcing metallic member 102, there is no particular limitation.
It may take any shape as long as the end portions of the back face
reinforcing metallic member are sufficiently covered by the resin.
For the thickness of the resin of covering the end portions of the back
face reinforcing metallic member, there is also no particular limitation
as long as the end portions of the back face reinforcing metallic member
are sufficiently covered by the resin. Even when the thickness of the
resin is relatively thinned, there is provided an adequate protective
effect in terms of deterioration prevention of the metallic member as the
back face reinforcing metallic member.
For the resin 105 situated on the rear face of the back face reinforcing
metallic member, it is desired to be relatively thin in view of the
processing efficiency. In view of preventing the resin from being
separated, it is desired to be relatively thick. In any case, the
thickness of the resin situated on the rear face of the back face
reinforcing metallic member is not necessary to be constant.
In a preferred embodiment, it is made such that the end portions of the
back face reinforcing metallic member 102 are covered by a relatively
thick resin layer of the resin 105 and the resin layer is extended to
cover a partial area of the rear face of the back face reinforcing
metallic member at a thickness which is gradually thinned toward the
center of the rear face of the back face reinforcing metallic member.
The resin 105 is desired to have a flexibility or deformability which can
follow the movement of the back face reinforcing metallic member when bent
upon the bending treatment. Further, the resin 105 is desired to have a
sufficient adhesion with the back face reinforcing member, as previously
described. In addition, the resin 105 is desired to have a certain
physical strength also in order to prevent the occurrence of layer
separation at the interface between the filler and the back face
reinforcing metallic member.
The resin 105 is desired to comprise a thermoplastic resin. Such
thermoplastic resin can include, for example, ethylene-vinyl acetate
copolymer (EVA), ethylene-acrylate copolymer (EEA), polyvinyl butyral
(PVB), silicone resin, and acrylic resin.
As the resin 105, it is possible to use the same material used as the
filler. In this case, there is provided an improvement in the working
efficiency in the production of a solar cell module.
Weatherable Film 103 (or Surface Protective Film)
The weatherable film 103 (or the surface protective film) is positioned at
the outermost surface of the solar cell module. It is required to excel in
weatherability, pollution resistance, transparency, water repellency, and
physical strength. In order for the weatherable film to have an improved
pollution resistance, it may contain a volatile component.
The weatherable film is necessary to have a property which can follow the
movement of the back face reinforcing metallic member when bent upon the
bending treatment, without being broken. And in general, the weatherable
film is desired to have a large elongation persentage.
Therefore, the weatherable film is comprised of an appropriate transparent
resin film which satisfies the above-described requirements. Such film can
include fluororesin films.
Specific examples of the fluororesin film are polyvinylidene fluoride resin
films, polyvinyl fluoride resin films, and tetrafluoroethylene-ethylene
copolymer films.
In order to attain a further improvement in the adhesion of the weatherable
film 103 with the filler 104, a given surface of the weatherable film to
be contacted with the filler is desired to be subjected to surface
treatment by way of corona discharge treatment, plasma treatment, ozone
treatment, or the like.
In the case where the resin film as the weatherable film comprises an
oriented resin film, there is a tendency for the oriented film to be
cracked. Therefore, the resin film as the weatherable film is desired to
comprise a non-oriented resin film.
Filler 104
The filler 104 serves to encapsulate the photovoltaic element 101 (or the
solar cell) so as to form a layer of the filler in which the photovoltaic
element is embedded while the irregularities present at the periphery of
the photovoltaic element being filled by the filler and which has opposite
faces, one being contacted with the weaterable film 103 and the other
being contacted with the back face reinforcing member 102.
The filler 104 is desired to excels in workability because the back face
reinforcing metallic member is subjected to bending treatment.
The filler 104 situated on the light incident side is required to have a
property of adequately allowing light used for photoelectric conversion to
transmit therethrough to arrive at the photovoltaic element 101 so that a
sufficient photoelectric conversion efficiency is attained by the
photovoltaic element.
The filler 104 is desired to be constituted by an appropriate resin which
can be desirably bonded with not only the photovoltaic element 101 but
also the back face reinforcing metallic member 102 and the weatherable
film 103 with a sufficient adhesion.
As most desirable examples of such resin, there can be mentioned
thermoplastic resins. The use of these thermoplastic resins as the filler
104 enables to readily encapsulate the photovoltaic element 101 while
sufficiently filling the irregularities present at the periphery of the
photovoltaic element, resulting in forming a layer of the filler 104 in
which the photovoltaic element is embedded in a desirable state and which
has flat opposite faces, one being bonded with the weaterable film 103
with a sufficient adhesion and the other being bonded with the back face
reinforcing member 102 with a sufficient adhesion.
Specific examples of the thermoplastic resin usable as the filler 104 are
ethylene-vinyl acetate copolymer (EVA), ethylene-acrylate copolymer (EEA),
polyvinyl butyral (PVB), silicone resin, and acrylic resin.
In order for the filler 104 to have an improved heat resistance, the filler
104 may contain a crosslinking agent, thermal oxidation preventive agent
or the like.
In order for the the filler 104 to have a improved weatherability, the
filler may contain an UV absorber.
Further, the filler 104 may contain an appropriate sheet-like
filler-retaining member such as a sheet-like woven or nonwoven glass fiber
member or a sheet-like woven or nonwoven polypropylene fiber member in a
state that the filler-retaining member is embedded in the filler.
For the thickness of the filler 104, it is preferably in the range of from
0.3 mm to 2 mm.
By the way, the filler 104 situated on the rear side of the photovoltaic
element 101 may comprise a opaque resin. Particularly in this respect, the
filler 104 may be configured to have a plurality of different regions each
constituted a different resin. For instance, a surface side region of the
filler 104 situated on the light incident side of the photovoltaic element
is constituted by a specific resin (a light transmissive (or transparent)
resin) and a back side region of the filler situated on the rear side of
the photovoltaic element is constituted by other appropriate resin, or a
region of the filler where the photovoltaic element is present is
constituted by said specific resin and the remaining region of the filler
where no photovoltaic element is present is constituted other appropriate
resin.
Now, for the solar cell module according to the present invention, it is
not always necessary to have such opposite bent non-power generation
regions as shown in FIG. 1. It may be used as it is in a state without
having being subjected to bending treatment by way of
plasticity-processing.
In the present invention, for the shape of the bent portion of the solar
cell module which is formed by way of plasticity-processing, there is no
particular limitation.
The formation of the bent portion may be conducted by means of bending
treatment, press working or the like.
In any case, the bent portion is desired to comprise a non-power generation
region with no photovoltaic element which has been plasticity-processed.
In the case of forming the bent portion by means of the bending treatment,
it is desired to bend a predetermined non-power generation region of the
solar cell module at a gentle bending angle R while having a due care so
that neither film nor resin are damaged or separated. For the direction in
which the non-power generation region is bent by means of the bending
treatment, it is possible to bend the non-power generation region toward
the light receiving face side of the photovoltaic element, toward the rear
side of the photovoltaic element, or toward these two sides so that the
non-power generation region is shaped to have a desired configuration. In
this case, there is no particular limitation for the manner of the bending
treatment and also for a bending equipment employed in the bending
treatment.
In order to prevent the surface of the solar cell module from being damaged
in the bending treatment, to use a blade, die or roll which are made of a
material which hardly damages the surface of the solar cell module is
desirable. In the bending treatment using any of these instruments, it is
possible to use a soft resin member made of an urethane resin or the like
at a portion of the solar cell module which is contacted with the
instrument.
The solar cell module according to the present invention may be installed
at a desired location. For instance, it may be installed on a roof of a
building, in terms of effective utilization of the ground and also in
terms of burglarproof and the like. This is not limitative, but it may be
installed at other appropriated location, for example, on the ground, a
support table or the like.
As previously described, the solar cell module with no bent non-power
generation region according to the present invention may be produced by
way of thermocompression bonding process. For instance, it may be produced
by a manner of forming a stacked body comprising the foregoing constituent
members for a solar cell module on a mounting table of a laminator,
covering the stacked body by a covering sheet so as to hermetically
enclose the stacked body between the covering sheet and the mounting
table, and heating and uniting the stacked body while exhausting the space
containing the stacked body between the covering sheet and the mounting
table, followed by cooling to room temperature while continuing the
vacuuming operation, and returning the inside of the space containing the
stacked body between the covering sheet and the mounting table to
atmospheric pressure to take out the treated stacked body.
In the following, the present invention will be described in more detail
with reference to examples which are not intended to restrict the scope of
the present invention.
EXAMPLE 1
In this example, there were prepared two solar cell modules having the
configuration shown in FIGS. 1 and 2.
Each solar cell module was prepared in a manner shown in FIGS. 4 and 5.
FIG. 4 is a schematic cross-sectional view illustrating a stacked body in
process for the preparation of a solar cell module formed on a mounting
table of a laminater. FIG. 5 is a schematic cross-sectional view
illustrating a thermocompressed stacked body as a solar cell module
situated on the mounting table.
In FIGS. 4 and 5, reference numeral 401 indicates a solar cell element (or
a photovoltaic element), reference numeral 402 a back face reinforcing
metallic member, reference numeral 403 a light transmissive surface
protective film having a weatherability, reference numeral 404 a filler,
reference numeral 405 a resin for covering an end portion of the back face
reinforcing member 402, and reference numeral 406 a mounting table of a
laminater (not shown).
The laminater (not shown) comprises said mounting table 406 and a heat
resistant silicone rubber sheet (not shown) which serves to enclose an
object comprising a stacked body (to be subjected to thermocompression
treatment) positioned on the mounting table. The mounting table 406 is
made of a stainless steel and it is provided with a heating mechanism such
as an electric heater (not shown) for heating the object. The mounting
table 406 is also provided with a heat resistant O-ring (not shown) and an
exhaust system connected to a vacuum pump (not shown).
Each solar cell module was prepared as will be described below.
1. Provision of solar cell 401:
As the solar cell 401, there was provided a solar cell comprising three
photovoltaic elements of the configuration shown in FIG. 3, integrated in
series connection.
The solar cell was prepared in the following manner.
(1). Preparation of three photovoltaic elements:
Each photovoltaic element was prepared in the following manner.
There was first provided a well-cleaned stainless steel plate as a
substrate 301. On the substrate 301, there was formed a two-layered back
reflecting layer 302 comprising a 5000 .ANG. thick Al film/a 5000 .ANG.
thick ZnO film by means of the conventional sputtering process. On the
back reflecting layer 302 thus formed, there was formed a tandem type
amorphous silicon (a-Si) photoelectric conversion semiconductor layer as
as a semiconductor photoactive layer 303 comprising a 150 .ANG. thick
n-type amorphous silicon layer/a 4000 .ANG. thick i-type amorphous silicon
layer/a 100 .ANG. thick p-type microcrystalline silicon layer/a 100 .ANG.
thick n-type amorphous silicon layer/a 800 .ANG. thick i-type amorphous
silicon layer/a 100 .ANG. thick p-type microcrystalline silicon layer
laminated in the named order from the substrate side by means of the
conventional plasma CVD process, wherein each n-type amorphous silicon
layer was formed using SiH.sub.4 gas, PH.sub.3 gas and H.sub.2 gas, each
i-type amorphous silicon layer was formed using SiH.sub.4 gas and H.sub.2
gas, and each p-type microcrystalline silicon layer was formed using
SiH.sub.4 gas, BF.sub.3 gas and H.sub.2 gas. Then, on the semiconductor
photoactive layer 303, there was formed a 700 .ANG. thick transparent and
electrically conductive layer 304 composed of In.sub.2 O.sub.3 by means of
the conventional heat resistance evaporation process wherein an In source
was evaporated in an O.sub.2 atmosphere. Successively, an Ag-paste
comprising powdery Ag dispersed in a polyester resin was screen-printed on
the transparent and electrically conductive layer 304, followed by drying,
to thereby form a grid electrode as a collecting electrode 305. As for the
resultant, a copper tub as a negative side power outputting terminal was
fixed to the substrate 301 using a stainless solder, and a tin foil tape
as a positive side power outputting terminal was fixed to the collecting
electrode 305 using an electrically conductive adhesive. Thus, there was
obtained a photovoltaic element.
The above procedures were repeated to obtain three photovoltaic elements.
(2). Preparation of solar cell:
The three photovoltaic elements obtained in the above step (1) were
linearly arranged, and they were integrated in series connection by
electrically connecting the positive side power outputting terminal of one
photovoltaic element to the negative power outputting terminal of the
other photovoltaic element adjacent to the former photovoltaic element by
using a solder.
Thus, there was obtained a solar cell.
In this way, there were prepared two solar cells.
2. Preparation of solar cell module:
Using each of the two solar cells obtained in the above 1, there were
prepared two solar cell modules of the configuration shown in FIGS. 1 and
2.
Each solar cell module was prepared in the manner shown in FIGS. 4 and 5.
As the back face reinforcing metallic member 402, there was provided a 0.4
mm thick Zn-plated steel plate coated by a polyester resin (trademark
name: COLORGRIP, produced by Daidokohan Kabushiki Kaisha) having a pair of
wiring holes of 15 mm in diameter through which the pair of power
outputting terminals of the solar cell can be wired to the outside.
As the filler 404, there were provided two 900 .mu.m thick EVA
(ethylene-vinyl acetate copolymer) sheets having a weatherability
(trademark name: EVAFLEX 150, produced by Mitsui-Du Pont Chemical
Company).
As the resin 405, there was provided a EVA (ethylenevinyl acetate
copolymer) sheet having a weatherability (trademark name: EVAFLEX 150,
produced by Mitsui-Du Pont Chemical Company).
As the surface protective film 403, there was provided a 50 .mu.m thick
ETFE (ethylene-tetrafluoroethylene copolymer) film (trademark name: AFLEX,
produced by Asashi Glass Kabushiki Kaisha) having a corona-discharged
surface to be contacted with the EVA sheet 404.
The size of each of the back face reinforcing metallic member 402, EVA
sheets 404 and the ETFE film 403 was made to be greater than that of the
solar cell 401. However, the size of the back face reinforcing member 402
was made to be smaller than those of the EVA sheets 404 and the ETFE film
403. The EVA sheet as the resin 405 was made to have a shape capable of
covering the peripheral end portions of the back face reinforcing metallic
member 402.
As shown in FIG. 4, on the surface of the mounting table 406, there were
laminated the ETFE film 403, the EVA sheet 404, the solar cell 401, the
EVA sheet 404, and the back face reinforcing metallic member 402 in the
named order, followed by laminating the EVA sheet 405 so as to cover the
peripheral end portions of the back face reinforcing metallic member 402,
to thereby form a stacked body situated on the mounting table 406.
Then, the above-described heat resistant silicone rubber sheet (not shown)
was superposed over the stacked body on the mounting table 406 while
sealing between the mounting table and the silicone rubber sheet by means
of the above-described heat resistant O-ring (not shown). Thereafter, the
above-described vacuum pump (not shown) was operated to exhaust the inside
of the space containing the stacked body between the silicone rubber sheet
and the mounting table 406 through the above-described exhaust system to a
vacuum degree of about 10 Torr, where the silicone rubber sheet was sagged
toward the mounting table 406 to compress the stacked body. While
continuing the vacuuming operation by the vacuum pump, the stacked body
was subjected to heat treatment at 150.degree. C. for 30 minutes by means
of the above-described heating mechanism. Thereafter, while still
continuing the vacuuming operation by the vacuum pump, the stacked body
was air-cooled to room temperature. The operation of the vacuum pump was
terminated to return the inside of the space containing the stacked body
between the silicone rubber sheet and the mounting table 406 to
atmospheric pressure, followed by removing the silicone rubber sheet (see,
FIG. 5). Then, the treated stacked body was taken out from the mounting
table. The treated stacked body was found to have unnecessary external
projections comprising EVA resin. The projections were cut to remove. The
resultant was found to have an EVA resin layer 405 (see, FIG. 5) extending
to the rear face of the back face reinforcing metallic member 402 to cover
a partial area of the rear face while covering the peripheral end portions
of the back face reinforcing member. The extended EVA resin layer situated
on the rear face of the back face reinforcing metallic member 402 was
found to have a maximum thickness of 0.5 mm and the EVA resin layer of
covering the peripheral end portions of the back face reinforcing metallic
member was found to be 2 mm in thickness.
3. Shaping:
Using a molding equipment, the solar cell-free opposite side end portions
of the resultant were bent as shown in FIG. 1.
Thus, there was obtained a solar cell module having opposite bent portions
in which the solar cell 401 is sealed by the filler 404, the surface
protective film 403 and the back face reinforcing metallic member 402 and
which has a resin layer of covering the peripheral end portions of the
back face reinforcing metallic member 402 while the rein layer being
extended to also cover a partial area of the rear face thereof.
In this way, there were obtained two solar cell modules having the
configuration shown in FIGS. 1 and 2.
Evaluation
For the resultant two solar cell modules, evaluation was conducted by way
of salt spray test and acid rain cycle test.
(1) The salt spray test:
One of the two solar cell modules was subjected to repetition of a cycle
comprising spraying a 5 wt. % salt water having a pH value of 7.0 for 2
hours, drying for 4 hours and moisture-wetting for 2 hours 180 times.
(2) The acid rain cycle test:
The remaining solar cell module was subjected to repetition of a cycle
comprising spraying an acid rain solution of pH 3.5 (composed of 5 wt. %
neutral NaCl solution, nitric acid and NaOH aqueous solution) for 24 hours
and drying for 24 hours 24 times.
As a result, in both the salt spray test and the acid rain cycle test,
neither rust nor color change were occurred at the entire of the back face
reinforcing member. In addition, neither bulging nor layer separation were
occurred at the filler not only in the solar cell-bearing portion but also
in the solar cell-free bent portions.
EXAMPLE 2
The procedures of Example 1 were repeated, except that as the back face
reinforcing metallic member, a 0.4 mm thick galvernized steel plate
(trademark name: TIMERCOLOR GL, produced by Daidokohan Kabushiki Kaisha)
coated by a polyester resin was used, to thereby obtain two solar cell
modules having the configuration shown in FIGS. 1 and 2.
For the resultant two solar cell modules, evaluation was conducted by way
of the salt spray test and the acid rain cycle test in the same manner as
in Example 1.
As a result, in both the salt spray test and the acid rain cycle test,
neither rust nor color change were occurred at the entire of the back face
reinforcing member. In addition, neither bulging nor layer separation were
occurred at the filler not only in the solar cell-bearing portion but also
in the solar cell-free bent portions.
EXAMPLE 3
In this example, there were prepared two solar cell modules having the
configuration shown in FIGS. 1 and 2.
Each solar cell module was prepared in a manner shown in FIGS. 6, 7 and 8.
FIG. 6 is a schematic cross-sectional view illustrating a stacked body in
process for the preparation of a solar cell module formed on a mounting
table of a laminater. FIG. 7 is a schematic cross-sectional view
illustrating a thermocompressed stacked body as a solar cell module
situated on the mounting table. FIG. 8 is a schematic cross-sectional view
showing the configuration of an end portion of the thermocompressed
stacked body removed from the mounting table.
In FIGS. 6, 7 and 8, reference numeral 601 indicates a solar cell element
(or a photovoltaic element), reference numeral 602 a back face reinforcing
metallic member, reference numeral 603 a light transmissive surface
protective film having a weatherability, reference numeral 604 a filler,
and reference numeral 606 a mounting table of a laminater (not shown).
The laminater (not shown) comprises said mounting table 606 and a heat
resistant silicone rubber sheet (not shown) which serves to enclose an
object comprising a stacked body (to be subjected to thermocompression
treatment) positioned on the mounting table. The mounting table 606 is
made of a stainless steel and it is shaped to have a protruded table with
a cross section in a trapezoid-like form having a circular necking in
order to establish a space between the rear face of the back face
reinforcing member 602 for a resin fluid to be flown thereinto. This
protruded table may be a protruded area circumscribed by a recession such
as a groove on the mounting table 606. The recession in this case serves
as said space.
The mounting table 606 is provided with a heating mechanism such as an
electric heater (not shown) for heating the object. The mounting table 606
is also provided with a heat resistant O-ring (not shown) and an exhaust
system connected to a vacuum pump (not shown).
Each solar cell module was prepared as will be described below.
1. Provision of solar cell 601:
As the solar cell 601, there was provided a solar cell comprising three
photovoltaic elements of the configuration shown in FIG. 3, integrated in
series connection.
The solar cell was prepared in accordance with the procedures described in
the step 1 in Example 1 for the preparation of a solar cell.
In this way, there were prepared two solar cells.
2. Preparation of solar cell module:
Using each of the two solar cells obtained in the above 1, there were
prepared two solar cell modules of the configuration shown in FIGS. 1 and
2.
Each solar cell module was prepared in the manner shown in FIGS. 6, 7 and
8.
As the back face reinforcing metallic member 602, there was provided a 0.4
mm thick Zn-plated steel plate coated by a polyester resin (trademark
name: COLORGRIP, produced by Daidokohan Kabushiki Kaisha) having a pair of
wiring holes of 15 mm in diameter through which the pair of power
outputting terminals of the solar cell can be wired to the outside.
As the filler 604, there were provided two 900 .mu.m thick EVA
(ethylene-vinyl acetate copolymer) sheets having a weatherability
(trademark name: EVAFLEX 150, produced by Mitsui-Du Pont Chemical
Company).
As the surface protective film 603, there was provided a 50 .mu.m thick
ETFE (ethylene-tetrafluoroethylene copolymer) film (trademark name: AFLEX,
produced by Asashi Glass Kabushiki Kaisha) having a corona-discharged
surface to be contacted with the EVA sheet 604.
The size of each of the back face reinforcing metallic member 602, EVA
sheets 604 and the ETFE film 603 was made to be greater than that of the
solar cell 601. And the size of each of the two EVA sheets 604 was made to
be greater than those of the back face reinforcing metallic member 602 and
the ETFE film 603.
As shown in FIG. 6, on the surface of the protruded table of the mounting
table 606, there were laminated the back face reinforcing metallic member
602, the EVA sheet 604, the solar cell 601, the EVA sheet 604 and the ETFE
film 603 in the named order to thereby form a stacked body situated on the
protruded table of the mounting table 606.
Then, the above-described heat resistant silicone rubber sheet (not shown)
was superposed over the stacked body on the protruded table of the
mounting table 606 while sealing between the mounting table 606 and the
silicone rubber sheet by means of the above-described heat resistant
O-ring (not shown). Thereafter, the above-described vacuum pump (not
shown) was operated to exhaust the inside of the space containing the
stacked body between the silicone rubber sheet and the mounting table 606
through the above-described exhaust system to a vacuum degree of about 10
Torr, where the silicone rubber sheet was sagged toward the mounting table
606 to compress the stacked body. While continuing the vacuuming operation
by the vacuum pump, the stacked body was subjected to heat treatment at
150.degree. C. for 30 minutes by means of the above-described heating
mechanism, where the EVA sheets 604 were fluidized to flow into the space
between the necking of the protruded table of the mounting table 606 and
the back face reinforcing member 602 while covering the entire of the
peripheral end portions of the back face reinforcing member 602 as shown
in FIG. 7. Thereafter, while still continuing the vacuuming operation by
the vacuum pump, the thus treated stacked body was air-cooled to room
temperature. The operation of the vacuum pump was terminated to return the
inside of the space containing the treated stacked body between the
silicone rubber sheet and the mounting table 606 to atmospheric pressure,
followed by removing the silicone rubber sheet. Then, the treated stacked
body was taken out from the mounting table 606.
By this, there was obtained a product having the configuration shown in
FIG. 8. The product was found to have unnecessary external projections
comprising EVA resin. The projections were cut to remove. The resultant
was found to have an EVA resin layer 604 (see, FIG. 8) extending to the
rear face of the back face reinforcing metallic member 602 to cover a
partial area of the rear face while covering the peripheral end portions
of the back face reinforcing metallic member. The extended EVA resin layer
situated on the rear face of the back face reinforcing metallic member 602
was found to have a maximum thickness of 0.5 mm and the EVA resin layer of
covering the peripheral end portions of the back face reinforcing metallic
member was found to be 2 mm in thickness.
The solar cell-free opposite side end portions of the resultant were bent
as shown in FIG. 1 in the same manner as in Example 1.
Thus, there was obtained a solar cell module having opposite bent portions
in which the solar cell 601 is sealed by the filler 604, the surface
protective film 603 and the back face reinforcing metallic member 602 and
which has a resin layer of covering the peripheral end portions of the
back face reinforcing member 602 while the rein layer being extended to
also cover a partial area of the rear face thereof.
In this way, there were obtained two solar cell modules having the
configuration shown in FIG. 1.
For the resultant two solar cell modules, evaluation was conducted by way
of the salt spray test and the acid rain cycle test in the same manner as
in Example 1.
As a result, in both the salt spray test and the acid rain cycle test,
neither rust nor color change were occurred at the entire of the back face
reinforcing member. In addition, neither bulging nor layer separation were
occurred at the filler not only in the solar cell-bearing portion but also
in the solar cell-free bent portions.
EXAMPLE 4
The procedures of Example 3 were repeated, except that the protruded table
of the mounting table 606 was changed to a protruded table with a cross
section in a trapezoid-like form having a linear necking capable of
establishing a space between the rear face of the back face reinforcing
metallic member for a resin fluid to be flown thereinto, to thereby obtain
a solar cell module having peripheral end portions configured as shown in
FIG. 9.
Particularly, the solar cell module obtained has solar cell-free opposite
bent portions as shown in FIG. 1 and in which as shown in FIG. 9, the
solar cell (not shown) is sealed by the filler 904, the surface protective
film 903 and the back face reinforcing metallic member 902 and the solar
cell module has an EVA resin layer of covering the peripheral end portions
of the back face reinforcing metallic member 902 while the rein layer
being extended to also cover a partial area of the rear face thereof as
shown in FIG. 9.
The extended EVA resin layer situated on the rear face of the back face
reinforcing metallic member 902 was found to have a maximum thickness of
0.2 mm and the EVA resin layer of covering the peripheral end portions of
the back face reinforcing metallic member was found to be 1 mm in
thickness.
In this way, there were obtained two solar cell modules having the
configuration shown in FIG. 1.
For the resultant two solar cell modules, evaluation was conducted by way
of the salt spray test and the acid rain cycle test in the same manner as
in Example 1.
As a result, in both the salt spray test and the acid rain cycle test,
neither rust nor color change were occurred at the entire of the back face
reinforcing member. In addition, neither bulging nor layer separation were
occurred at the filler not only in the solar cell-bearing portion but also
in the solar cell-free bent portions.
EXAMPLE 5
In this example, there were prepared two solar cell modules having the
configuration shown in FIG. 10.
In FIG. 10, reference numeral 1001 indicates a solar cell enclosed in the
solar cell module, reference numeral 1002 a back face reinforcing metallic
member, and reference numeral 1005 an EVA resin layer.
Each solar cell module was prepared in the following manner.
The procedures of the steps 1 and 2 of Example 1 were repeated to obtain a
solar cell module.
The resultant solar cell module was subjected to bending treatment using a
roller forming equipment having a pair of pressure rollers capable of
conveying a sheet at a constant speed while press-forming the sheet, where
each of the solar cell-free opposite end portions was passed through
between the pressure rollers to intermittently bend several positions
thereof to obtain a solar cell modules having opposite portions each
having been bent at several positions thereof as shown in FIG. 10.
Thus, there were obtained two solar cell modules having the configuration
shown in FIG. 10.
For the resultant two solar cell modules, evaluation was conducted by way
of the salt spray test and the acid rain cycle test in the same manner as
in Example 1.
As a result, in both the salt spray test and the acid rain cycle test,
neither rust nor color change were occurred at the entire of the back face
reinforcing metallic member. In addition, neither bulging nor layer
separation were occurred at the filler not only in the solar cell-bearing
portion but also in the solar cell-free bent portions.
EXAMPLE 6
The procedures of Example 1 were repeated, except that the EVA sheet as the
resin 405 to cover the peripheral end portions of the back face
reinforcing metallic member 402 was replaced by an EEA resin
(ethylene-acrylate copolymer resin; trademark name: EVAFLEX-EVA, produced
by Mitsui Du Pont Chemical Kabushiki Kaisha) sheet, to obtain two solar
cell modules having the configuration shown in FIGS. 1 and 2.
For the resultant two solar cell modules, evaluation was conducted by way
of the salt spray test and the acid rain cycle test in the same manner as
in Example 1.
As a result, in both the salt spray test and the acid rain cycle test,
neither rust nor color change were occurred at the entire of the back face
reinforcing metallic member. In addition, neither bulging nor layer
separation were occurred at the filler not only in the solar cell-bearing
portion but also in the solar cell-free bent portions.
COMPARATIVE EXAMPLE 1
The procedures of the steps 1 and 2 of Example 1 were repeated, except that
the peripheral end portions of the back face reinforcing metallic member
was exposed without being covered by the EVA resin layer as in Example 1,
to thereby obtain two solar cell modules having the configuration shown in
FIG. 11. In FIG. 11, reference numeral 1102 indicates a back face
reinforcing metallic member with no cover, reference numeral 1103 a
surface protective film, and reference numeral 1104 an EVA filler.
The solar cell-free opposite end portions of each solar cell module were
bent in the same manner as in Example 1.
Thus, there were obtained two solar cell modules having the opposite bent
end portions.
For the resultant two solar cell modules, evaluation was conducted by way
of the salt spray test and the acid rain cycle test in the same manner as
in Example 1.
As a result, in both the salt spray test and the acid rain cycle test,
corroded products were generated on all over the cut faces of the back
face reinforcing metallic member and the back face reinforcing metallic
member was partly rusted. In addition, on the front side of the solar cell
module, the occurrence of a color change was observed at a portion of the
back face reinforcing metallic member which is some centimeters distant
from the edge. Further in addition, bulging and layer separation were
occurred at the filler not only in the solar cell-bearing portion but also
in the solar cell-free bent portions.
COMPARATIVE EXAMPLE 2
In this comparative example, there were prepared two solar cell modules
having the configuration shown in FIGS. 12 and 13.
FIG. 12 is a schematic slant view of the entire of a solar cell module
having opposite bent portions and having a coated, curved stainless steel
plate fitted to an end portion of the flat area of the solar cell module.
FIG. 13 is a schematic cross-sectional view, taken at the line B-B' in
FIG. 12.
In FIGS. 12 and 13, reference numeral 1201 indicates a solar cell enclosed
in the solar cell module, reference numeral 1202 a back face reinforcing
metallic member, reference numeral 1203 a surface protective film,
reference numeral 1204 a filler, reference numeral 1206 a coated stainless
steel plate curved at 180.degree., and reference numeral 1207 a silicone
sealant.
Each solar cell module was prepared in the following manner.
The procedures of the steps 1 and 2 of Example 1 were repeated, except that
the peripheral end portions of the back face reinforcing metallic member
was exposed without being covered by the EVA resin layer as in Example 1,
to thereby obtain a solar cell module having the same configuration as
that shown in FIG. 11.
The solar cell-free opposite end portions of the resultant solar cell
module were bent in the same manner as in Example 1.
Then, for the two solar cell module having the opposite bent portions, a
coated stainless steel plate 1206 having curved at 180.degree. was fitted
to an end portion of the flat area of the solar cell module. And the space
between the end of the flat area of the solar cell module and the
stainless steel plate 1206 was filled by a silicone sealant 1207.
Thus, there were obtained two solar cell modules having the configuration
shown in FIGS. 12 and 13.
For the resultant two solar cell modules, evaluation was conducted by way
of the salt spray test and the acid rain cycle test in the same manner as
in Example 1.
As a result, in both the salt spray test and the acid rain cycle test, no
problem was occurred at the back face reinforcing metallic member's
portion covered by the coated stainless steel plate but at the remaining
portion of the back face reinforcing metallic member not covered by the
coated stainless steel plate, corroded products were generated on all over
the cut faces of the back face reinforcing metallic member and the back
face reinforcing metallic member was partly rusted. In addition, on the
front side of the solar cell module, the occurrence of a color change was
observed at a portion of the back face reinforcing metallic member which
is some centimeters distant from the edge, where in addition, bulging and
layer separation were occurred at the filler.
COMPARATIVE EXAMPLE 3
In this comparative Example, there were prepared two solar cell modules
having opposite solar cell-free bent portions.
Each solar cell module was prepared in the following manner.
The procedures of the steps 1 and 2 of Example 1 were repeated, except that
the peripheral end portions of the back face reinforcing metallic member
was exposed without being covered by the EVA resin layer as in Example 1,
to thereby obtain a solar cell module having the same configuration as
that shown in FIG. 11.
The resultant solar cell module was subjected to bending treatment by means
of the roller forming equipment in the same manner as in Example 5 to
obtain a solar cell modules having opposite portions each having been bent
at several positions thereof as shown in FIG. 10.
Thus, there were obtained two solar cell modules having the configuration
shown in FIG. 10.
For the resultant two solar cell modules, evaluation was conducted by way
of the salt spray test and the acid rain cycle test in the same manner as
in Example 1.
As a result, in both the salt spray test and the acid rain cycle test,
corroded products were generated on all over the cut faces of the back
face reinforcing metallic member and the back face reinforcing metallic
member was partly rusted. In addition, on the front side of the solar cell
module, the occurrence of color changes was observed at edge portions of
the back face reinforcing metallic member. Further in addition, bulging
and layer separation were occurred at the filler not only in the solar
cell-bearing portion but also in the solar cell-free bent portions.
Further, in this comparative example, there was found a further problem.
That is, upon the introduction of the solar cell module into the roller
forming equipment, layer separation with a relatively large area was
occurred at a portion of the solar cell module contacted at a corner of
the pressure roller.
As above described, it is understood that the present invention provides
such pronounced advantages as will be described below.
By covering the end faces of the back face reinforcing metallic member by a
resin, the back face reinforcing metallic member is effectively prevented
from being deteriorated or corroded. This situation provides advantages in
that the coated film of the back face reinforcing metallic member, which
is situated in the vicinity of the end portions of the back face
reinforcing metallic member, is prevented from being colored, separated
and raised. And by covering a part of the rear face of the back face
reinforcing metallic member by an extended portion of said resin, layer
separation at the interface between the back face reinforcing member and
the filler is effectively prevented.
The above situations provides further advantages as will be described in
the following. Not only during the bending treatment of the solar cell
module but also during the transportation and installation of the solar
cell module, there is not such an occasion that the solar cell modules are
not damaged by the edge portions of their back face reinforcing members
when they are contacted with each other and therefore, the occurrence of a
defective solar cell module is prevented. In the case where the solar cell
module is subjected to bending treatment by means of the roller forming
equipment, the pressure rollers are prevented from being worn. Further, it
is not necessary to use a metallic cover in order to prevent the back face
reinforcing metallic member from being separated from the filler, and this
situation makes it possible to establish a desirable roof of a simple
configuration and having a good exterior appearance when the solar cell
module is used as a roof member of a building. In this case, since such
metallic cover as above described is not used, there is free of a problem
found in the case of using the metallic cover in that dusts or the like
are accumulated on the metallic cover. And there can be attained a
reduction in the costs required in the roofing by solar cell modules.
Further in addition, the protected solar cell-free end portions of the
solar cell module according to the present invention can be bent into a
complicate configuration as desired, which is satisfactory in terms of
protection.
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